Method of producing a black oxid on the surface of steel.



UNITED STATES PATENT OFFICE.

V EMIL JABULOWSKY, OF PFORZHEIM, GERMANY.

METHOD OF PRODUCING A BLACK OXID ON THE SURFACE OF STEEL.

Specification of Letters'Patent.

Patented Dec. 18, 1906.

To a, whmn it may concern.-

Be it known that I, EMIL JABULowsKY, manufacturer, a subject of theGerman Emperor, residing at Pforzheim, Germany, have invented a certainnew or Improved Method for Producing a Layer of Black OXid on theSurface of Steel, of which the following is a specification.

This invention relates to a new or improved process for the treatment ofsteel ornaments and other articles of steel for the purpose ofproducingon the surfaces of such articles layers of polished black oxid.

According to the present invention steel articles of any kind are firsthighly polished and then placed in a bed of faintly incandescentcarbon-powder, in which they are left for a longer or shorter period,according to the thickness of the metal, the said articles not beingremoved from the carbon-powder until their surfaces are blackened. Theblackened surfaces are again polished, and the articles are then readyfor use. Before polishing the blackened surfaces the steel articles arepreferably plunged while still hot into a paraffin-bath. By this meansgreater uniformity of blackness is obtained.

I claim The process for the purpose set forth consisting in polishingthe steel article, placing the latter in incandescent carbonowder toblacken its surface, immersing t e article while hot in a paraflin-bath,and polishing the article, substantially as described.

In Witness whereof I have signed this specification in the presence oftwo witnesses.

EMIL JABULOWSKY.

Witnesses:

GUSTAV SoHWEIss, M. C. BRITTAIN.

